With the development of a carrier-grade Ethernet, in order to make the Ethernet achieve the carrier-grade standard, a higher demand is put forward to a protection and a switch of the Ethernet. An existing Provider Backbone Bridge Traffic Engineering (PBB-TE) protection switch technology currently supports a protection for a Traffic Engineering Service Instance (TESI), that is, an end-to-end tunnel protection. The end-to-end protection solution not only has a relatively long protection switch time, but also involves too many nodes, and can not protect intermediate links and nodes thereof. Once a certain intermediate link or a certain node fails, the entire TESI must be switched; and if a plurality of TESIs pass through the failed link or node, the plurality of TESIs must be switched too. That is to say, the protected objects of the PBB-TE end-to-end protection are TESIs. When it is detected that a certain working TESI fails, it is needed to re-encapsulate a user message, which enters the PBB-TE tunnel, with another protection TESI, so that the traffic can pass through the protection PBB-TE tunnel. For the Ethernet, the link protection and the node protection are part of the Ethernet protection, and most network failures occur on a certain link or node, therefore, a PBB-TE segment protection becomes more important, and several operators have proposed a requirement on the PBB-TE segment protection, that is, a protection segment is specially configured in a working segment of the PBB-TE tunnel to protect the working segment. The working segment and the protection segment form an Infrastructure Protection Group (IPG).
FIG. 1 shows a schematic diagram of a PBB-TE segment protection according to a relevant art. As shown in FIG. 1, a protection group contains one working segment and one or a plurality of protection segments. In a normal case, if no failure is detected on the working segment, all traffic protected by the PBB-TE segment protection group is forwarded on the working segment. Once the working segment fails or a certain management command is received, a Segment Edge Bridge (SEB) of an end point segment of the PBB-TE segment protection group can detect the failure in time, then the SEB would trigger update of a forwarding database (FDB), so that an egress port in the forwarding database corresponding to a TESI protected by the protection domain IPG is modified to be an egress port corresponding to the protection segment on the SEB, and the traffic is switched to the protection segment. In this way, the protection for the working segment is realized, the normal forwarding of the network traffic is guaranteed and the reliability of a network is improved. At present, a project has been set up for the technology of the PBB-TE segment protection in a standard organization of the Institute of Electrical and Electronics Engineers (IEEE). This project not only supports 1:1 PBB-TE segment protection, but also provides a solution of M:1 PBB-TE segment protection, that is, an M:1 PBB-TE segment protection group consists of one working segment and M protection segments, wherein the M (M is greater than 1) protection segments protect the one working segment. This solution can greatly improve the reliability of a system.
In a Connectivity Check Message (CCM) detection mechanism of the PBB-TE segment protection, the mechanism adopted in a failure detection is implemented by a CCM defined in the 802.1ag standard.
FIG. 2 shows a schematic diagram of a PBB-TE segment and a failure detection mechanism thereof according to a relevant art. As shown in FIG. 2, there is one segment in a PBB-TE network, with two end points being a Segment Edge Port (SEP) 1 and an SEP2 at port ends, wherein, SEB can be a Backbone Edge Bridge (BEB) apparatus in the PBB-TE network, also can be a Backbone Core Bridge (BCB) apparatus; both the SEP1 and the SEP2 are Provider Network Ports (PNPs), and a Segment Intermediate Bridge (SIB) apparatus on Segment Intermediate Ports (SIPs) of this segment can be a BCB. A Media Access Control (MAC) address of the SEP1 is MAC1 and an MAC address of the SEP2 is MAC2. It is needed to configure an Ethernet Switch Path (ESP) for a CCM on the intermediate apparatus SIB of the segment to forward the CMM. A 3-tuple of an ESP1 from the SEP2 to the SEP1 is <MAC1, MAC2, BVID1>; a 3-tuple of an ESP2 from the SEP1 to the SEP2 is <MAC2, MAC1, BVID2>, in which, MAC is the acronym of Media Access Control and BVID is the acronym of Bridge Local Area Network Identifier (BVID). A CCM1 sent from the SEP 2 to the SEP1 would carry the 3-tuple of <MAC1, MAC2, BVID1> and be forwarded along the path of the ESP1; a CCM2 sent from the SEP1 to the SEP2 would carry the 3-tuple of <MAC2, MAC1, BVID2> and be forwarded along the path of the ESP2. Through the CCM1 and the CCM2, the failure detection on the segment between the SEP1 and the SEP2 is implemented.
FIG. 3 shows a schematic diagram of a PBB-TE working segment, a PBB-TE protection segment, an SEB and an SIB according to a relevant art. As shown in FIG. 3, wherein
a member segment refers to a working segment or a protection segment of o protection group, wherein the working segment refers to one segment through which traffic passes when no failure is detected on the segment;
the protection segment refers to one segment which bears the traffic after the occurrence of a switch due to the detection of a failure on the working segment or the reception of a switch management command;
a pair of SEBs are two end points configured to terminate a segment, wherein the SEB can be a BEB apparatus in a PBB-TE network, or can be a BCB apparatus; bridge apparatus within the segment are SIBs.
IPG traffic switch refers that a group of TESI traffic protected by the IPG is redirected to the protection segment from the working segment, or to the working segment from the protection segment, wherein the redirection generally is implemented by modifying an egress port of a corresponding table entry of the TESI in a forwarding database.
However, in many cases, it is very difficult to configure multiple protection segments for one working segment and it might be limited by various conditions, such as network resources and the like.